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Color Blindness

Topic Overview

What is color blindness?

Color blindness means that you
have trouble seeing red, green, or blue or a mix of these colors. It's rare
that a person sees no color at all.

Color blindness is also called
a color vision problem.

A color vision problem can change your
life. It may make it harder to learn and read, and you may not be able to have
certain careers. But children and adults with color vision problems can learn
to make up for their problems seeing color.

What causes color blindness?

Most color vision
problems are inherited (genetic) and are present at
birth.

People usually have three types of cone cells in the eye.
Each type senses either red, green, or blue light. You see color when your cone
cells sense different amounts of these three basic colors. The highest concentration of cone cells are
found in the
macula, which is the central part of the
retina.

Inherited color blindness happens when you don't have one of these types
of cone cells or they don't work right. You may not see one of these three
basic colors, or you may see a different shade of that color or a different
color. This type of color vision problem doesn't change over time.

A color vision problem isn't always inherited. In some cases, a person
can have an acquired color vision problem. This can be caused by:

What are the symptoms?

You may be able to see some colors but not others. For instance, you may not be able to tell the difference between
some reds and greens but can see blue and yellow easily.

You may see many colors, so you may not know
that you see color differently from others.

You may only be able
to see a few shades of color, while most people can see thousands of colors.

In rare cases, some people see only black, white, and gray.

How is color blindness diagnosed?

Tests measure
how well you recognize different colors.

In one type of test, you look at sets of
colored dots and try to find a pattern in them, such as a letter or number. The
patterns you see help your doctor know which colors you have trouble with.

In another type of test, you arrange colored chips in order
according to how similar the colors are. People with color vision problems
cannot arrange the colored chips correctly.

Because a color vision problem can
have a big impact on a person's life, it is important to detect the problem as
early as possible. In children, color vision problems can affect learning
abilities and reading development. And color vision problems may limit career choices that require you to tell colors apart. Most experts
recommend eye exams for children between ages 3 and 5. Vision screening is
recommended for all children at least once before entering school, preferably
between the ages of 3 and 4.

How is it treated?

Inherited color vision problems
cannot be treated or corrected.

For the most common type of color blindness—red-green color deficiency—no treatment is needed, because you function normally. You may not be aware that you do not see colors the way they are seen by others.

Some acquired color vision
problems can be treated, depending on the cause. For example, if a cataract is
causing a problem with color vision, surgery to remove the cataract may restore
normal color vision.

You can find ways to help make up for a color
vision problem, such as:

Wearing colored contact lenses. These may help you see differences between colors. But these lenses don't
provide normal color vision and can distort objects.

Wearing glasses that block glare. People with severe
color vision problems can see differences between colors better when there is
less glare and brightness.

Learning to look for cues like brightness or location, rather than colors. For example, you can learn the
order of the three colored lights on a traffic signal.

How can you help a child who has color blindness?

Color vision problems may make it harder for children to learn and read, which
can lead to poor schoolwork and low self-esteem.

You can help your
child these ways.

Make sure your child is tested for color
vision problems during routine eye tests. The sooner you know there is a
problem, the sooner you can help your child. Eye exams should be done at all well-child visits.footnote 1

Tell your child's
teachers and other school staff about the problem. This may be helpful. Suggest seating your child
where there is no glare and using a color of chalk that your child can see.

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